Use snprintf() to format SSID in patty_ax25_ntop()

src/ax25.c

@@ -1,3 +1,4 @@
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
@@ -77,22 +78,6 @@ error_invalid_callsign:
     return -1;
 }
 
-static inline int expt(int base, int e) {
-    int ret;
-
-    if (e == 0) {
-        return 1;
-    }
-
-    ret = base;
-
-    while (--e) {
-        ret *= ret;
-    }
-
-    return ret;
-}
-
 int patty_ax25_ntop(const patty_ax25_addr *addr,
                     char *dest,
                     size_t len) {
@@ -118,29 +103,16 @@ int patty_ax25_ntop(const patty_ax25_addr *addr,
     }
 
     if (ssid) {
-        int place = 2;
+        int formatted;
 
-        if (o == len) {
-            goto error_overflow;
-        }
-
-        dest[o++] = '-';
-
-        while (place--) {
-            int div = expt(10, place),
-                num = ssid / div;
-
-            if (num) {
-                if (o == len) {
-                    goto error_overflow;
-                }
-
-                dest[o++] = '0' + num;
-            }
+        if ((formatted = snprintf(&dest[o], 1 + len - o, "-%d", ssid)) < 0) {
+            goto error_format_ssid;
+        } else {
+            o += formatted;
         }
     }
 
-    if (o == len) {
+    if (o > len) {
         goto error_overflow;
     }
 
@@ -148,6 +120,7 @@ int patty_ax25_ntop(const patty_ax25_addr *addr,
 
     return 0;
 
+error_format_ssid:
 error_overflow:
     errno = EOVERFLOW;